The present disclosure relates generally to the manufacturing of semiconductor devices, and more particularly to a photolithography process in semiconductor manufacturing.
Photolithography is frequently used for forming the components of integrated circuits. Generally, an exposure tool includes a photomask or reticle, through which light beams pass through and are focused by a projection lens onto a wafer, resulting in an image of the integrated circuits in a photoresist layer of the wafer.
There has been a continued increase in the density of devices that can be placed on a chip and as a result, the printing of device feature patterns with extremely small spacings is required. However, there is a minimum pitch printing resolution limit which is determined by the wavelength of the light beam and the numerical aperture of the exposure tool. The pitch is the distance from one device feature to the next adjacent device feature. If the pitch becomes too small, the projected image may be distorted by so called “proximity effects” that are associated with the diffraction of light.
Therefore, what is needed is an improved and cost-effective method for satisfying minimum pitch requirements of current photolithography tools.